GPZ spike Detector


Posted on Feb 7, 2014

This circuit detects spikes in voltage around 18v. It is used to detect when a battery becomes disconnected on a running motorcycle. When that happens, the regulator is unable to maintain a steady voltage so the voltage fluctuates wildly. Even though the average voltage may remain near 14v, the instantaneous voltage can be extremely high leading t


GPZ spike Detector
Click here to download the full size of the above Circuit.

o a large RMS voltage. This over-voltage can burn out electronics and lighting in the vehicle. This circuit detects the peak voltages and when there is significant peak voltage, a red LED lights up as a warning. C1 is used to make the circuit less sensitive to transient spikes which don`t contain much energy. This prevents false warnings. Only a spike with significant energy will set off the detector. If the voltage is pure DC, the threshold voltage is near 18v. If the voltage is in the form of a spike, the threshold is higher. The less energy the spike contains, the higher the threshold will be. Since spikes can be very brief, the LED normally would only flash very briefly. In order to make the LED stay on for a longer period, C2 is added. When a spike is detected above the threshold, LED1 is lit and C2 charges very rapidly through R3. When the spike is gone, Q1 turns off and the base of Q2 gets current from C2, thus keeping the LED lit while C2 discharges. The layout of Q2, LED1, R4, and C2 is such that Q2 is in the active region when the LED is lit. This means the base current of Q2 is very small. This was done so Q2 would discharge slowly while keeping the LED lit.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Mini Metronome
    PIC controlled DDS VFO
    ic-7805 based 5V breadboard mini PSU circuit with explanation
    Low Voltage Step-Down Converter
    Off lining switching power supply solution of OnSemiNCP107515W low power consumption
    doorknob alarm pcb
    Simple Infrared Remote Control Extender
    Additional formula LP Recorder increased compensation circuit diagram image HQ
    INA321 322 a low-cost medium accuracy ECG machine ECG amplifier
    CD4520 CD4511 CD4067 digital automatic inspection circuit diagram



    Top